1. Field of the Invention
The present invention relates to a magnetic recording and reproducing device which records magnetic data by application of heat and magnetic field and magnetically reproduces the magnetic data, and to a magnetic recording medium.
2. Description of the Related Art
There has been a remarkable increase in areal density of magnetic recording media such as hard discs by various improvements including reduction in the grain size of magnetic particles forming the magnetic recording layer, material changes, and increased precision in the processing of magnetic heads, and a further improvement in the areal density is expected.
As the increase in the areal density leads to thermal instability, it is preferable to use material that has high magnetic anisotropy, which exhibits high coercivity, for the magnetic recording layer; however, with conventional magnetic heads, it was hard to apply a stronger magnetic field than the coercivity of such a high magnetic anisotropy material, i.e., recording and deleting of magnetic data were hard to achieve.
Meanwhile, there has been known a magnetic recording and reproducing device that projects electron beam to the magnetic recording layer to reduce the coercivity by heat so as to achieve recording and reproducing of magnetic data (see, for example, Japanese Patent Laid-Open Publication No. 2001-250201).
With this method, however, it was hard to precisely magnetize only a target portion of the magnetic recording layer, because the peripheral part of the portion to which electron beam is projected is also heated by heat conduction, and because the temperature distribution of the heated portion and the magnetic field distribution of the magnetic head are not uniform. The data recording and reproducing precision was accordingly low.
The recording and reproducing precision could be improved if the minimum area for recording data were made large enough, but this would reduce the areal density.